Manufacturers of microelectronic devices are continually reducing the size and increasing the density of components in integrated circuits to increase the speed and capacity of devices and reduce the power consumption. Complex series of manufacturing protocols, inspection protocols, and testing protocols are often performed to produce microelectronic devices, such as light-emitting diodes (LEDs), integrated circuits, and microelectromechanical systems (MEMS). It may be difficult to rapidly and accurately detect defects in microelectronic devices. For example, microelectronic devices often include circuitry with vias that are formed by depositing conductive material into openings (e.g., through-holes) in wafers. The conductive material may deposit faster at the edges of the openings than within the holes, and the build-up of conductive material at the openings may inhibit deposition of conductive material at central regions of the holes resulting in voids or other defects. These voids are commonly referred to as keyholes. A scanning electron microscope (SEM) image can be visually inspected to locate and identify keyholes. However, it is difficult to locate and accurately identify keyholes because SEM images often have significant noise and low contrast, and keyholes often vary in size and shape.
Conventional automated systems can compare patterns to identify defects. For example, a conventional automated system can compare a pattern in a captured image to a reference pattern and identify defects based on the comparison. Conventional automated systems can also measure critical dimensions that are necessary to the function of the component. Unfortunately, reference patterns or critical dimensions have to be known before performing pattern comparison or critical dimension measurements. Additionally, detection rates of potential defects using pattern comparison or critical dimension measurements can decrease significantly when analyzing images with irregular shaped features (e.g., keyholes), significant noise, and low-contrast.